sql server 2005中新增加的try catch学习

sql server 2005中新增加的try catch，可以很容易捕捉异常了，今天大概学习看了下，归纳下要点如下

基本用法
BEGIN TRY     {  sql_statement |  statement_block  }END TRYBEGIN CATCH     {  sql_statement |  statement_block }END CATCH
，和普通语言的异常处理用法差不多，但要注意的是，SQL SERVER只捕捉那些不是严重的异常，当比如数据库不能连接等
这类异常时，是不能捕捉的
一个例子：
BEGIN TRY  DECLARE @X INT  -- Divide by zero to generate Error  SET @X = 1/0  PRINT 'Command after error in TRY block'END TRYBEGIN CATCH  PRINT 'Error Detected'END CATCHPRINT 'Command after TRY/CATCH blocks'






  
另外try catch可以嵌套
Begin TRY  delete from GrandParent where Name = 'John Smith'  print 'GrandParent deleted successfully'End TryBegin Catch   Print 'Error Deleting GrandParent Record'   Begin Try     delete from Parent where GrandParentID =      (select distinct ID from GrandParent where Name = 'John Smith')     Print 'Parent Deleted Successfully'   End Try   Begin Catch     print 'Error Deleting Parent'     Begin Try       delete from child where ParentId =      (select distinct ID from Parent where GrandParentID =      (select distinct ID from GrandParent where Name = 'John Smith'))       print 'Child Deleted Successfully'     End Try     Begin Catch       Print 'Error Deleting Child'     End Catch   End Catch End Catch
另外，SQL SERVER 2005在异常机制中，提供了error类的方法方便调试，现摘抄如下，比较简单，不予以解释
ERROR_NUMBER(): Returns a number associated with the error.
ERROR_SEVERITY(): Returns the severity of the error.
ERROR_STATE(): Returns the error state number associated with the error.
ERROR_PROCEDURE(): Returns the name of the stored procedure or trigger in which the error occurred.
ERROR_LINE(): Returns the line number inside the failing routine that caused the error. 
ERROR_MESSAGE(): Returns the complete text of the error message. The text includes the values supplied for any substitutable parameters, such as lengths, object names, or times.






 
最后举例子如下，使用了error类的方法
BEGIN TRY  DECLARE @X INT  -- Divide by zero to generate Error  SET @X = 1/0  PRINT 'Command after error in TRY block'END TRYBEGIN CATCH  PRINT 'Error Detected'  SELECT ERROR_NUMBER() ERNumber,         ERROR_SEVERITY() Error_Severity,         ERROR_STATE() Error_State,         ERROR_PROCEDURE() Error_Procedure,         ERROR_LINE() Error_Line,         ERROR_MESSAGE() Error_MessageEND CATCHPRINT 'Command after TRY/CATCH blocks'

最后输出
Error DetectedErr_Num Err_Sev Err_State Err_Proc             Err_Line  Err_Msg------- ------- --------- -------------------- --------- --------------------------------8134        16          1 NULL                 4        Divide by zero error encountered.